US2418160A

US2418160A - Starting and controlling apparatus for electric discharge lamps

Info

Publication number: US2418160A
Application number: US516419A
Authority: US
Inventors: John H Campbell
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1943-12-31
Filing date: 1943-12-31
Publication date: 1947-04-01
Anticipated expiration: 1964-04-01

Description

April 1, J. CAMPBELL 2,418,160

STARTING AND CONTROLLING APPARATUS FOR ELECTRIC DISCHARGE LAMPS Filed Dec. 51, 1943 Ifiventor: John H. Campbell, W 6. x

His Attorney.

Patented Apr. 1, 1947 STARTING AND CONTROLLING APPARATUS FOR ELECTRIC DISCHARGE LAB PS John H. Campbell, Schene General Electric Com New York ctady, N. Y., assignor to pany, a corporation of Application December 31, 1943, Serial No. 516,419

9 Claims.

My invention relates to apparatus for starting and controlling electric discharge devices such as discharge lamps of the fluorescent type. As is well known, discharge lamps require a higher voltage for starting than for their subsequent operation. Such lamps in common use at the present time have filamentary electrodes and have apparatus associated therewith by which heating current is passed through the electrodes to heat them to an electron emitting temperature before the starting voltage is applied thereto. As a result of recent developments in the construction of such lamp electrodes the lamps may be started without prior heating of the electrodes, that is, started cold cathode without serious injury to the electrodes. It is the object of my invention to provide improved apparatus for producing the voltage necessary to effect the starting of such lamps without preheating their electrodes. A further object of my invention is to provide apparatus which while effective to start a lamp will also control its subsequent operation with the attendant energy losses reduced to a low value.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Referring to the drawing, Fig. 1 is a circuit diagram illustrating an embodiment of my invention and Fig. 2 is a like diagram illustrating a modification.

Referring first to Fig. 1, two electric discharge devices I and 2 which, for example, may be 40 watt fluorescent lamps of similar construction each having the filamentary or thermionic electrodes 3, are connected to be operated in parallel from the source of alternating current supply 4. The source may be a 60 cycle, 118 volt lighting circuit and the connection therewith is shown controlled by the line switch 5. Connected between the lamp circuits and the source 4 I employ suitable means, such as the auto-transformer 6, for stepping up the voltage of the source to a somewhat higher value, for example 330 volts. In the circuit of the lamp l is the lamp ballast reactor 8, which for example may have the same impedance as the reactor 1; thus both lamps are in lagging current circuits, their ballasts being inductive.

As mentioned above, the lamps which I employ,

thermionic electrodes, do nothave their electrodes preheated but rather are started cold cathode. I obtain the voltage necessary so to start the lamps in the parallel connected circuits illustrated by means of circuits which shunt the lamps and which include fixed circuit elements which circuits I shall now describe. Connected in shunt with the lamp l is the capacitor 9 whose impedance may, for example, be 5300 ohms and the reactor It which is constructed to saturate at the voltage applied thereto upon. the closing of the switch 5 and before the lamps start. In its saturated condition the impedance of that reactor may, for example, be 635 ohms. As soon as the lamps start the reactor l9 desaturates and in its desaturated condition its impedance may, for example, be 1050 ohms. Connected in shunt with the lamp 2 is the capacitor ll whose impedance may, for example, be the same as that of the capacitor 9 and the same reactor ill, the latter being common to the two lamp shunting circuits. Inasmuch as the circuits of lamps i and 2 are both inductive, I have shown the capacitor 52 whose impedance may, for example, be 530 ohms connected across the secondary of the transformer 6 in order to improve the power factor of the energy drawn from the source of supply. As a result of the circuit which I have shown and have described above the voltages applied to the lamps I and 2 are sufiicient to cause them immediately to break down upon the closing of the switch 5 after which they continue to operate on lagging current circuits with but slight energy loss in the circuits shunting them.

In the modified form of my invention shown by Fig. 2, I have substituted like reactors l3 and it for the capacitors 9 and ii of Fig. 1 and substituted the capacitor l5 for the reactor is of thatfigure, it being understood that the reactances of the substituted members, although not the same as the reactances of the members in Fig. 1 for which they are substituted, are such that the voltages applied to the lamps when the switch 5 is closed are sufiicient to cause the lamps to start. Moreover during their operation but slight energy loss occurs in the lamp shunting circuits.

The reactive members 9, l l and I5 being capacitors and the reactive members It, I3 and I4 being reactors will be spoken of for convenience as having reactances which are opposite in character inasmuch as the reactive voltage which although provided with occurs across a capacitor is opposite to that which occurs across a reactor.

What'I claim as new and desire to secure by Letters Patent oi the United States is:

1. In combination, a plurality of inductively reactive lamp circuits having reactances of like character each arranged to include an electric discharge lamp having a pair of electrodes, said circuits being connected together to be supplied in parallel from a source of alternating current supply, a reactive circuit connected to shunt each lamp, the reactance of each shunt circuit being capacitive prior to conduction by said lamps and including a pair of serially connected reactive impedance elements connected between electrodes of different lamps and a common reactive impedance element connected between the common juncture of the serially connected impedance elements and other electrodes of said lamps.

2. In combination, a plurality of inductively reactive lamp circuits each arranged to include an electric discharge lamp having a pair of electrodes, said circuits being connected together to be supplied in parallel from a source of alternating current supply, and means connected directly across electrodes of different lamps and including a capacitive circuit connected to shunt each of said lamps, said shunt circuits including a reactive member common thereto.

3. In combination, a plurality of inductively reactive lamp circuits each arranged to include an electric discharge lamp trodes, said circuits being connected together to having a pair of elecbe supplied in parallel from a source of alternating current supply, and means connected across electrodes of difierent lamps and including a capacitive circuit connected to shunt each of said lamps, each of said shunt circuits including inductive and capacitive reactive members and said shunt circuits including a reactive member in common.

4. In combination, a plurality of inductively reactive lamp circuits each arranged to include an electric discharge lamp having a pair of electrodes, said circuits being connected together to be supplied in parallel from a source of alternating current supply, and means connected across electrodes of difierent lamps and including a capacitive circuit including a reactor connected to shunt one of said lamps and a capacitive circuit including the same reactor connected to shunt another of said lamps.

5. In combination, a plurality of inductively reactive lamp circuits each arranged to include an electric discharge lamp having a pair of electrodes, said circuits being connected together to be supplied in parallel from a source of alternating current supply, and means connected directly across electrodes of different lamps comprising a pair of serially-connected capacitors, one of said capacitors and a reactor connected in series across one of said lamps and the other capacitor and said reactor connected in series across another of said lamps.

6. In combination, a plurality of inductively reactive lamp circuits each arranged to include an electric discharge lamp having a pair of electrodes, said circuits being connected together to be supplied in parallel from a source of alternating current supply, and means connected directly across electrodes of different lamps comprising a pair of serially-connected reactors, a capacitive circuit including one of said reactors and 'a-capacitor connected to shunt one of said lamps and a capacitive circuit including the same capactitor and the other of said reactors connected to shunt another of said lamps.

'7. In combination, a plurality of inductively reactive lamp circuits each arranged to include an electric discharge lamp having a pair of electrodes, said circuits being connected together to be supplied in parallel from a source of alternating current supply, means connected directly across electrodes of different lamps comprising a pair of serially connected reactors, one of said reactors and a capacitor connected in series across one of said lamps, and the other reactor and said capacitor connected in series across another of 'said lamps.

8. In combination, a plurality of inductively reactive lamp circuits each arranged to include an electric discharge lamp, said circuits being connected together to be supplied in parallel from a source of alternating current supply, a capacitive circuit including a reactor connected to shunt one of said lamps and a capacitive circuit including the same reactor connected to shunt another of said lamps, said reactor being constructed to saturate at the voltage applied thereto before the lamps start and to desaturate after they start.

9. In combination, a plurality of inductively reactive lamp circuits each arranged to include an electric discharge lamp, said circuits being connected together to be supplied in parallel from a source of alternating current supply, a capacitor and a reactor connected in series across one of said lamps and a capacitor and said reactor connected in series across another of said lamps, said reactor being constructedto saturate at the voltage applied thereto before the lamps start and to desaturate after they start.

JOHN H. CAMPBELL.

1 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS